Apparatus for bending glass sheets



April 30, 1963 F. J- CARSON ET AL APPARATUS FOR BENDING GLASS SHEETS 2 Sheets-Sheet 1 Filed June 23, 1958 3 3 a m. 3 9 E NTI I5 3. U 9 m? 3 5 3 3 S 3 on R) J J N S n: L 5 0N 3 S 5 S 5 3 8 A 3 3 l 3 S 3 3 .q

m Q m: m L XL 9 9 Q 2 3 m 9 a. N. ll i 5 w April 30, 1963 F. J. CARSON ETAL APPARATUS FOR BENDING GLASS SHEETS 2 Sheets-Sheet 2 Filed June 25, 1958 INVENTORS em, mu!

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V 3,087,317 Patented Apr. 30, 1963 fire 3,087,317 APPARATU FQR BENDING GLASS SIIEETEv Frank J. Carson and Herbert A. Leflet, In, Toledo, Ohio, assignors to Lihhey-tJwens-Ford Glass Company, Toledo, Ohio, a corporation of Ohio Filed dune 23, 1958, Ser. No. 743,92ii 11 Claims. (til. 65-238) The present invention relates generally to apparatus for bending glass sheets or plates, and more particularly to an improved bending mold.

In the bending of glass sheets to form bent sheets having their peripheral edges in compression, thus providing a more shock resistance sheet, there have been two generally accepted types of bending molds used. One of these molds, upon which a pattern cut sheet is bent, is provided with a shaping rail or surface of such a size that when the glass sheet is bent into conformity therewith the marginal periphery of the sheet overhangs the rail and, therefore, cools without being materially affected by the residual heat within the rail and thus sets in compression.

In the other type of mold, which is used for bending blank or block size glass sheets which are cut to pattern outline after being bent, the shaping rail is substantially rectangular in plan view and a heat retaining member or strain bar having its periphery contoured to the desired outline for the pattern cut sheet, but somewhat smaller as compared thereto, is located within the rectangular shaping rail and spaced downwardly therefrom. After the glass sheet is bent into contact with the shaping rail, and while the mold is passing through the furnace annealing zone, the residual heat within the heat retaining member prevents the portion of the sheet thereabove from cooling at the same rate as intermediate portions of the sheet outwardly therefrom between the periphery of the strain bar and the shaping rail which causes the intermediate sheet portions to set in compression. In cutting a sheet bent in such a manner to form a patterned sheet, the scoring tool is moved over the glass along a path through the sheet portion set in compression so that the resultant pattern cut sheet will have its peripheral edge in compression.

Such a mold and a procedure for bending block size sheets for subsequent cutting to pattern shape was disclosed in our earlier application Serial No. 574,329, filed March 27, 1956, now Patent No. 2,893,170, issued July 7, 1959.

As explained in the earlier case, when relatively long glass sheets are to be bent in a mold of the last mentioned type, it is also desirable to support the sheet intermediate the ends thereof to prevent excessive deflection of the sheet when supported on the mold prior to the bending thereof. Various types of intermediate supports for the sheet have been used with varying degrees of success, and which usually comprised auxiliary movable arms or pivots which extend upwardly from the mold and engaged the glass sheet. However, the excessive use of metal in the areas of the glass sheet adjacent the mold is not desirable since the mass of the metal adversely affects the proper heating of the sheet and may set-up undesirable stress patterns in the sheet during the cooling thereof. In accordance with the present invention, there is provided a glass bending mold adapted to produce a bent glass sheet having a desirable stress pattern therein and also adapted to support the sheet intermediate the ends thereof without inducing undesirable stress patterns in the sheet.

It is, therefore, an important object of the invention to provide a novel and improved bending mold for bending glass sheets and particularly sheets of substantial length.

Another object of the invention is to provide an improved glass bending mold adapted to form a desired stress pattern in the sheet and also to support the sheet intermediate the ends thereof prior to and during bending.

A further object of the invention is to provide a glass bending mold adapted to form a desired stress pattern in the sheet and to support the sheet intermediate the ends thereof and to accomplish both of the above results through use of a minimum amount of metal adjacent the glass.

Other objects and advantages of the invention will become more apparent during the course of the following description when taken in connection with the accompanying drawings.

In the drawings, wherein like numerals are employed to designate like parts throughout the same:

FIG. 1 is a plan view of an improved bending mold provided by the present invention in the open position;

FIG. 2 is a transverse section taken along line 22 of FIG. 1;

FIG. 3 is a fragmentary plan view of the improved bending mold provided by the present invention in the closed position;

FIG. 4 is a longitudinal section taken along line 4-4 of FIG. 1; and

FIG. 5 is an enlarged fragmentary perspective view of the improved sheet support and stress forming member of the invention.

With reference now to the drawings and particularly to FIGS. 1 to 4 there is shown a glass bending apparatus 10 constructed in accordance with the invention and comprising a substantially rectangular rack or support frame 11 having vertical support posts 12 extending upwardly from each of the four corners thereof for pivotally supporting the bending mold proper. This mold 13 is of the skeleton type and includes a center section 14 and a pair of oppositely disposed movable end sections 15 immediately adjacent the opposite ends of the center section 14 and forming substantially continuations thereof.

Each of the mold end sections 15 comprises a substantially triangular or V-shaped shaping rail 16 formed as an inverted T and having a relatively narrow upper surface for receiving the bent glass sheet in contact therewith. The center mold section 14 comprises a pair of spaced, substantially straight parallel shaping rails 17 having a relatively shallow curvature and of the same configuration aligned with the innermost ends of the substantially V-shaped end section rails 16 and preferably connected thereto by hinges 18.

Carried within the confines of the shaping rail sections forming the mold center section and mold end sections is a heat retaining member in the form of a strain bar 19 of substantially greater width than the relatively narrow upper surface of the respective shaping rail. The strain bar 19 is normally disposed below the sheet contacting surfaces of the shaping rails and has its outermost edges shaped to conform to the outline of the pattern to be cut from the bent sheet but somewhat smaller.

As best shown in FIGS. 1 and 2 the strain bar 19 comprises a triangular or substantially V-shaped end section 20 rigidly secured to each triangular shaped end rail section 16 by transverse rods 21 or in some other suitable manner. As shown in FIG. 1 each of the end sections 20 has its upper relatively wide surface 22 spaced from the mold shaping surface a substantially equal distance throughout its entire length and also has the upper surface 22 contoured to a configuration which is substantially identical with the end section shaping rails 16.

The portion of the strain bar 19 carried by the mold center section 1- 1 includes a pair of fixed spaced substantially parallel portions 23 and intermediate movable substantially parallel portions 24 which, as will be later set forth in detail, comprise an important feature of the present invention. The fixed portions 23 are located bea neath the shaping rails 17 at the opposite ends thereof and are carried by rods 21 which extend between the shaping rails. The relatively Wide or flat upper surface of the fixed portions are contoured to conform to the shaping surface of the center section rail 17. Each center or intermediate portion 24 is supported for movement from an elevated position wherein a flat glass sheet is placed on the mold to a lowered position when the sheet is bent, which lowered position places the intermediate portions in alignment with the fixed spaced portions 23 to form substantially continuations thereof.

As shown in FIG. 4 the adjacent ends of the respective strain bar sections 23 and 24 are beveled in such a manner as to provide a substantially continuous strain bar when the mold is closed. To support the elongated intermediate or center bar portion 24 for movement from the elevated to the lowered position there is provided a pair of curved elongated arms 25 having their outermost ends secured to the transversely extending pivot rods 26 of the end section which are swingably carried by the corner posts 12 and their innermost ends pivotally carrying downwardly disposed links '27 having their lowermost ends pivotally secured to rods 28 depending from the opposite ends of the bar section 24-. When the mold is in the open position the various parts assume the position shown in FIGS. 1, 2 and 4 and when the mold moves from the open to the closed position the various parts assume the position shown in FIG. 3. When the mold sections move from the open to the closed position the arms 25 are rotated downwardly thus carrying the intermediate bar sections 24 therewith and into alignment With the strain bar sections 23.

Carried by the intermediate bar sections 24 .are a plurality of sheet support blocks 29 preferably formed of a refractory material which will not fuse to the glass sheet. As shown in FIG. 4 the support blocks 29 adjacent the center of the intermediate bar section 24 have a greater height .as compared to the blocks 29 carried at the opposite ends of the intermediate bar section 24 so that the upper surface of the plurality of blocks lie in a horizontal support plane which is defined by the upper surfaces of the triangular shaping rail sections 16 at the apices thereof. Thus when the mold is in the position of FiG. 4 the glass sheet or sheets 30 are supported at their opposite ends upon the rail sections 16 and intermediate their ends upon the plurality of blocks 29.

As shown in FIGS. 1 and 3 the blocks 29 are secured to the edges of the bar sections 24 toward the shaping rails 17 when in their mounted position upon the bar sections 24. Due to this arrangement the intermediate bar sections 24 present an unbroken width substantially equal in Width to the fixed sections 23 exposed to the glass sheet as shown in FIG. 1. There is thus presented to the unders'urface of the glass sheet a substantially continuous strain bar of substantially equal width along its entire closed length and thus as will be later set forth .a stress pattern is formed in the glass sheet 30 through the action of the strain bar.

As Will be seen in FIG. 1, the movable sections 24 of the strain bar 19 are relatively wider than fixed sections and 23 and project outwardly thereof toward the shaping rails. The blocks 29 are fitted over the outer projecting edges of the bar sections and for this purpose the blocks are provided with slots in which the bar sections are received. If desired the bar sections 24 may be notched along the edges toward the rails 17 to prevent movement of the blocks 29 along the bar sections in a direction which is substantially parallel to the longitudinal axis of the mold 13.

In bending a glass sheet or pair of sheets upon the novel mold of the present invention the mold sections are swung to the open position of FIGS. 1, 2 and 4 and a sheet placed upon the mold. During the bending of the sheet and while the sections are moving from the open to the closed position of FIG. 3 the arms lower the intermediate bars 24 downwardly thus lowering the central portion of the sheet 30 and depositing said sheet onto the center mold section. During the remaining small increment of closing movement the blocks 29 are lowered below the shaping surface of the center section shaping rails 17 while the intermediate bars 24- are carried into Contact and alignment with the stationary bars 23.

After the sheet has been bent and is being annealed the residual heat remaining in the shaping rail sections and the strain bar 19 causes the portion of the glass sheet immediately thereabove to cool at a decreased rate as compared to an intermediate sheet portion therebetween thus setting the enclosed sheet portion in compression. After the block size sheet has been cooled it is removed from the mold and out along a surface line between the shaping rail sections and the strain bars through the area of the glass sheet set in compression thus providing a pattern cut sheet having its peripheral edge in compression which is more shock resistant.

From the description of the improved bending mold of the present invention it will be apparent that not only is there provided apparatus for supporting a glass sheet intermediate its ends but also apparatus for producing the desired stress pattern in the glass sheet, both of such objects being accomplished with a minimum amount of metal in the mold that is in close proximity to the glass thus minimizing the formation of undesirable stress patterns in the sheet.

It is to be understood that the forms of the invention herewith shown and described is to be taken as a preferred embodiment of the same, and that various changes may be be resorted to without departing from the spirit of the invention or the scope of the subjoined claims.

We claim:

1. Apparatus for bending blank size glass sheets which are to be subsequently cut to a pattern outline, a frame having supporting members extending upwardly therefrom, a link member swingably carried by each of said supporting members, a bending mold including a pair of end sections and an intermediate section mounted for movement from an open position to a closed position on said link members, heat retaining means including spaced fixed members and spaced movable members positioned within said pattern outline, said fixed members being rigidly secured to said end sections, spaced legs extending downwardly from said spaced movable members, arms secured to said pivot members and extending above the lowermost ends of said legs, links swingably connected to said arms and said legs whereby said movable members will be moved above said intermediate section when said movable mold sections move to said open position, and a plurality of spaced sheet engaging members secured to said movable members to support the glass sheets when the mold is in the open position.

2. Apparatus for bending blank size glass sheets as claimed in claim 1, wherein the sheet engaging members are secured to the movable members along the outermost edges thereof.

3. Apparatus for bending blank size glass sheets as claimed in claim 1, wherein the sheet engaging members extend upwardly from the movable members in varying distances whereby the uppermost surfaces of the sheet engaging members lie in the same plane.

4. Apparatus for bending blank size glass sheets as claimed in claim 1, wherein the sheet engaging members are formed of a refractory material which Will not fuse to the glass sheets.

5. Apparatus for bending blank size glass sheets as claimed in claim 1, wherein the spaced movable members have substantially greater width than the spaced fixed members whereby the width of the exposed portion of said movable member adjacent the sheet engaging members is substantially equal to the Width of the fixed members.

6. Apparatus for bending glass sheets, a skeleton-type mold including a substantially continuous shaping rail made up of a plurality of sections and having a shaping surface thereon, a substantially continuous skeleton-type heat retaining member located inwardly of said shaping rail and comprising a plurality of separate portions arranged in end to end relation, means mounting one of said portions in fixed relation to and below the shaping surface of an adjacent section of said shaping rail, and means mounting another of said portions for movement relative to said shaping rail between a lower position below the shaping surface .and an upper sheet supporting position above the shaping surface of an adjacent section of said shaping rail.

7. An apparatus as defined in claim 6 and wherein said movable portion of the heat retaining member has an area wider than an adjacent fixed portion of said heat retaining member to provide a lateral extension on said movable portion and sheet supporting members are carried on .and confined to said lateral extension.

8. Apparatus as defined in claim 7 wherein said heat retaining member is of metal and said sheet supporting members of a refractory material.

9. Apparatus as defined in claim 6 wherein the adjacent ends of the separate portions of said heat retaining member are beveled to overlap in one position of said movable portion and provide substantial continuity to said skeleton-type heat retaining member.

10. Apparatus as defined in claim 6 wherein said shaping rail includes end sections and an intermediate section together with means mounting said end sections for movement between the open and closed positions of the mold,

6 and said heat retaining member includes a portion adjacent each of said end sections that is fixedly mounted relative thereto.

11. Apparatus as defined in claim 6 wherein said shaping rail includes end sections and an intermediate section together with means mounting said end sections for movement between the open and closed positions of the mold, the movable portion of said heat retaining member is located adjacent and is movable relative to said intermediate section of the shaping rail, and means are provided between said movable portion of said heat retaining member and an end section for moving the former into sheet supporting position upon movement of the latter between said open and closed positions.

References Cited in the file of this patent UNITED STATES PATENTS 2,240,349 Preston Apr. 29, 1941 2,348,278 Boyles et a1 May 9, 1944 2,646,647 Bamford et a1. July 28, 1953 2,720,729 Rugg Oct. 18, 1955 FOREIGN PATENTS 1,097,088 France Feb. 9, 1955 1,124,919 France July 9, 1956 1,128,601 France Aug. 27, 1956 745,992 Great Britain Mar. 7, 1956 764,448 Great Britain Dec. 28, 1956 768,982 Great Britain Feb. 27, 1957 

6. APPARATUS FOR BENDING GLASS SHEETS, A SKELETON-TYPE MOLD INCLUDING A SUBSTANTIALLY CONTINUOUS SHAPING RAIL MADE UP OF A PLURALITY OF SECTIONS AND HAVING A SHAPING SURFACE THEREON, A SUBSTANTIALLY CONTINUOUS SKELETON-TYPE HEAT RETAINING MEMBER LOCATED INWARDLY OF SAID SHAPING RAIL AND COMPRISING A PLURALITY OF SEPARATE PORTIONS ARRANGED IN END TO END RELATION, MEANS MOUNTING ONE OF SAID PORTIONS IN FIXED RELATION TO AND BELOW THE SHAPING SURFACE OF AN ADJACENT SECTION OF SAID SHAPING RAIL, AND MEANS MOUNTING ANOTHER OF SAID PORTIONS FOR MOVEMENT RELATIVE TO SAID SHAPING RAIL BETWEEN A LOWER POSITION BELOW THE SHAPING SURFACE AND AN UPPER SHEET SUPPORTING POSITION ABOVE THE SHAPING SURFACE OF AN ADJACENT SECTION OF SAID SHAPING RAIL. 